This invention relates to tube bending tools and more particularly to a manually operable tube bender especially suited for effecting bends in excess of 90 degrees.
Manually operated tools for bending tubing are quite old and well known in the art. For example, such tools are widely used by electricians for forming bends in an electrical conduit. Examples of commercial tube benders sold by Stride Tool Inc. and its predecessors are described and claimed in U.S. Pat. Nos. 4,379,360, 4,220,642, 4,289,872, 4,229,873, 4,343,496, 4,379,340, and 4,424,660 (“the Stride patents”). The tools described in the Stride patents are capable of bending tubes up to 180 degrees. While these tools have enjoyed longstanding commercial success, the tools are somewhat awkward for use in effecting bends in excess of 90 degrees because the handles, which are manipulated by an operator to effect the bend, cross over when a tube is being bent beyond 90 degrees. When the handles cross over, manipulation of the tool becomes somewhat awkward and difficult. Moreover, an operator in bringing his hands toward one another through the first 90 degrees after the cross over, an operator's force application is reversed and one is pulling one's hands apart or pressing with crossed arms.
Another tool that has been available commercially for a period of time requires disconnection of one of the handles after a 90 degree bend has been completed by unscrewing the handle from the tool element to which it is connected. The handle is then reconnected by threading it into other threaded recess to effect bending from 90 degrees up to 180 degrees.
Accordingly it would be desirable to produce a manually operated tube bender which is capable of effecting bends up to 180 degrees without handle cross over or the need to disconnect and reconnect one of the handles after 90 degrees of bending has been accomplished.